4-1-8 POWER SUPPLY CIRCUIT (For dbx
NR
Circuit)
(Refer to Figs. 6-23
an_d
6-24)
+ ISV
n------,-------..
(I)
..,
u
R58
330
TR5
25B764
7
..,
~
(I)
:::::
u
ci
IC?
..,
M5230L
,._
..,
u
R59
330
N
'°
i
'
ci
.,.
,0:
,n
(I)
!!?
CX)
N
0
a:
..,
'
(I)
u
Q
,n
0
:8
GND
o------+----+-----------------------1-----uGND
-ISV
n---------
------------------------u
-II.
6V
TR6
2S0863
Fig. 6-23 Power Supply Circuit for dbx
NR
Circuit
STARTER
STANDARD
1--+----1
VOLTAGE
GENERATOR
_>---_._---I
OVER
CURRENT
1-------<
PROTECTION
VOLTAGE
ADJ
'------+--------------------------~I
GNO
IC7 (M5230L)
is
an
IC
for the dual tracking regulator.
The tracking regulator
is
a stabilized power supply in
which a change in either the positive
or
negative
output
voltage due to the load ( or otherwise),
is
followed by a similar change in the other voltage.
When it
is
used for the
DC
amplifier, etc., any offset
voltage due to supply voltage fluctuation can be
prevented.
Figs.
6-23
and 6-24 show the power supply circuit
and
IC
M5230L block diagram respectively. In the
power supply circuit
of
Fig. 6-23, the output voltage
is
controlled by changing the reference voltage
BALANCE
ADJ
H
OU1
PUT
'-----I
OVER
CURRENT!-------<
4
(-)IN
p
UT
PROTECTION
Fig. 6-24
IC
M5230L Block
Digram
applied to Pin
Ci)
of
IC
(M5230L)
though
the
resistor dividing circuit consisting
of
R6
l,
R.69,
R60,
and VR 7. In addition, C38 sets the rise
tim
constant
of
the output voltage, improves the
ripple
suppres-
sion ratio, and improves the output noise
v~lt
age.
R64 and R65 are resistors for balancing
tle
positive
and negative output voltages. Though
th1
positive/
negative output voltage ratio
can
be
cliar--iged
by
changing this resistance ratio, the po1[tjve and
negative output voltages are made identical
1y-
making
R64 equal to R65.
----------------
SERVICE
MANUAL
GX-747dbx
----------------
17
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